At 01:50 PM 12/30/00 -0800, Tim Bray wrote:
>>But it would have to be done low, fast, and under the radar...
Okay, I'm at T+16 on the suggestion, and feeling low.
>2. the simple XLink element (I don't think you need extended, and
> by using simple you could graft the whole thing onto an XHTML
> <div> or some such).
>3. a namespace in which are defined a bunch of reserved
> role attribute values
>
>These things would look like web pages and would display
>nicely in a browser. The idea is that the xlinks would
>point to related resources of various types. The role
>namespace would contain precooked values for various
>kinds of related resources (e.g. css stylesheet, xsd
>schema, dtd) whose use is widespread enough to achieve
>some consensus. Obviously, you could have links to
>more than one dtd or xsd or whatever.
Sounds good. I've got a slightly lighter suggestion. The document at the
namespace URI could be any well-formed XML, but the only content in it
which matters for purposes of automated processing is simple XLinks.
Simple XLinks can contain three URI values: href, role, and arcrole. I'll
suggest that we use two of them: href, which must be dereferenceable, and
role, which is PURELY AN IDENTIFIER. (Maybe there's a place for arcrole as
well, I don't know.)
<simple xmlns:xlink="http://www.w3.org/1999/xlink" xlink:type="simple"
xlink:href="myschema.xsd" xlink:role="http://www.w3.org/TR/xmlschema-1/">
<simple xmlns:xlink="http://www.w3.org/1999/xlink" xlink:type="simple"
xlink:href="myschema.dtd" xlink:role="http://www.w3.org/TR/REC-xml">
<simple xmlns:xlink="http://www.w3.org/1999/xlink" xlink:type="simple"
xlink:href="myschema.rlx" xlink:role="http://www.xml.gr.jp/relax/">
<simple xmlns:xlink="http://www.w3.org/1999/xlink" xlink:type="simple"
xlink:href="myschema.css" xlink:role="http://www.w3.org/TR/REC-CSS2">
...etc...
This repeats the cardinal sin of dereferencing, but in a context I'd
consider safer. It separates content from identifier more cleanly, and
avoids the protocol dependence of MIME content-type negotiation.
I'd strongly suggest that all namespace declarations and other attribute
declarations must appear in the instance document - no defaulting allowed.
Maybe, maybe not. See what y'all think. I gotta get back to this chapter
on W3C XML Schema Description Language.
Simon St.Laurent
XML Elements of Style / XML: A Primer, 2nd Ed.
XHTML: Migrating Toward XML
http://www.simonstl.com - XML essays and books